Tread mold

Abstract

A mold for molding a tread, in particular of a tire, having first elements in relief and second elements in relief for cooperating in the molding configuration to form a molding element intended to mold a single cutout opening both on to the running surface of the tread and on to one of the lateral edges of said tread and to define at least one orifice intended to allow the rubber mix to pass during the molding of the tread.

We claim:  
     
       1. A mold for molding a tire provided with a tread of rubber mix, this tread having a running surface and two lateral faces axially defining said tread, said mold comprising in the molding configuration: 
       a peripheral ring formed of sectors having a molding surface for molding at least the running surface of the tread, each sector being movable towards or away from the axis of the mold,  
       two shells concentric to the peripheral ring, each having a molding surface for molding a lateral face of the tread, these shells being movable in the direction of the axis of the mold towards or away from each other,  
       at least one first element in relief projecting from the molding surface of at least one of said shells for molding a channel beneath the running surface of the tread,  
       at least one second element in relief projecting from the molding surface of a sector of the ring for molding a cutout in the tread,  
       this mold being characterized in that, in the molding configuration, said at least one first element in relief borne by said at least one shell cooperates with said at least one second element in relief borne by said sector to form a molding element for molding in at least one motif in relief of the tread pattern a cutout opening on to the running surface of the tread, said cutout being extended to the inside of the tread by a channel opening on to at least one lateral face of the motif in relief, said first and second elements in relief forming at least one orifice which is entirely defined by said first and second elements in relief, each orifice thus formed permitting the rubber mix to pass during molding to form a connecting element between walls defining the cutout molded by said molding element. 
     
     
       2. A mold according to  claim 1  wherein said at least one first element in relief is provided with a groove for receiving an end of said at least one second element in relief for ensuring cooperation between said two elements during the molding operation. 
     
     
       3. A mold according to  claim 1  wherein at least one of the shells is formed of two concentric rings assembled such that the ring bearing the first elements in relief can rotate relative to the other ring to facilitate demolding of the vulcanized tire. 
     
     
       4. A mold according to  claim 1  wherein at least one of the shells bearing said first elements in relief is provided with holes intended to allow introduction of said first elements in relief so that they project from the molding surface of said shell. 
     
     
       5. A mold for molding a tread comprising an outer face forming a contact surface, extended laterally by lateral faces, these lateral faces furthermore being connected by an inner face, the mold comprising, in the molding position: 
       at least two mold parts defining a closed volume corresponding to the volume of the tread to be molded, said mold parts having molding surfaces for molding the outer, inner and lateral faces of the tread,  
       at least one first element in relief for molding a channel opening on to at least one lateral face of the tread, cooperating with at least one second element in relief for molding an incision which opens on to at least one of the inner or outer surfaces of the tread, for molding a single cutout, said first and second elements defining at least one orifice to allow the rubber mix forming the tread to pass through during the operation of molding said tread.  
     
     
       6. A mold according to  claim 5  wherein said one first element in relief molding a channel opening at least on to one lateral face of a tread cooperates with said at least one second element in relief molding an incision which opens on to the outer surface of the tread and at least one third element in relief molding an incision which opens on to the inner surface to mold a single cutout, the incisions molded by the second and third elements in relief being connected together by means of the channel, and in that, at least one of the second or third elements in relief is arranged with the first element in relief to define at least one orifice to allow the rubber mix to pass to form a connecting bridge connecting walls defining the cutout.